Geologic time periods

This category is also used for geologic age and geologic time.
Subtopics:
Phanerozoic (13 items)
Precambrian (10 items)


Results listed by similarity [list alphabetically]
Precambrian basement structure map of the continental United States-an interpretation of geologic and aeromagnetic data

Principal basement structures formed during the Precambrian in the continental United States based on interpretation of regional aeromagnetic anomaly data of North America.

Info
U-Pb Isotopic Data and Ages of Detrital Zircon and Volcanic Zircon Grains from the Torok and Nanushuk Formations, Arctic Alaska, 2021

U-Pb isotopic data and associated ages of zircon grains from 27 sedimentary samples and one volcanic ash sample from this area. Data are provided in CSV format.

Info
U-Pb Isotopic Data and Ages of Detrital Zircon Grains and Graptolite Fossil Data from Selected Rocks from the Western Alaska Range, Livengood area, and Seward Peninsula, Alaska - 2018

U-Pb isotopic data and associated ages of detrital zircon grains and fossil identifications and age assignments from a select sedimentary rocks in this area. Data are provided in CSV format.

Info
Airborne magnetic and radiometric survey, Ironton, Missouri area

Digital flight line data for a high resolution horizontal magnetic gradient and radiometric survey over this area. Flight line spacing was 300 m, mean terrain clearance was 140 m. Includes flight line data for the magnetic gradient survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. Data are provided in CSV format, flight lines are provided in shapefile format.

Info
Complete analytical data for Jurassic igneous rocks in the Bald Mountain mining district, Nevada

Petrographic and geochemical analyses of 50 outcrop samples and 58 drill core samples.

Info
Cretaceous magmatic rocks of Alaska

Data derived from the 1994 map "Latest Cretaceous and Cenozoic magmatic rocks of Alaska" compiled by E.J. Moll-Stalcup, D.A. Brew, and T.L. Vallier, published (at 1:2,500,000 scale) in volume G-1 of "The Geology of Alaska" (GSA)

Info
Digital tabulation of stratigraphic data from oil and gas wells in the Santa Maria Basin and surrounding areas, central California coast

This report makes available a large well dataset so that subsurface stratigraphic data are available in digital form for use within a GIS and in construction of three-dimensional models to address regional stratigraphic and structural questions.

Info
Exposed Precambrian Bedrock in Part of Dickinson County, Michigan, and Marinette and Florence Counties, Wisconsin

Rock outcrop locations taken from geologic maps published from the 1940s until the late 1990s. Bedrock exposure locations were routinely recorded to provide both an indication of where direct observations were made, and as a guide for future investigations to expedite location of observable rock exposures. Data are provided in shapefile format.

Info
Geochemical analyses of rock samples collected from mineral deposits and intrusions of the Bokan Mountain peralkaline granitic complex, Prince of Wales Island, southeastern Alaska

Major and trace element chemistry of rock samples collected in this area, where surrounding rocks host numerous mineral deposits and occurrences. Data are provided in Microsoft Excel and CSV formats.

Info
Geochemical analyses of rock samples collected from the Dora Bay peralkaline igneous complex, Prince of Wales Island, southeastern Alaska

Geochemical analyses of rock samples collected by the U.S. Geological Survey from surface exposures of host rock and REE-mineralized pegmatites and felsic dikes in this area to provide information on potential sources of co-product and by-product critical elements in domestic mineral deposits and to allow comparison with other REE deposits in peralkaline igneous complexes. Data are provided in CSV format.

Info
Geochemical and Modal Data for Mesoproterozoic Igneous Rocks of the St. Francois Mountains, Southeast Missouri

A compilation of new and previously published geochemical and modal analyses of Mesoproterozoic igneous rocks in this area. Includes major and trace element geochemistry and mineralogical composition as well as sample locations and characteristics. Data for 618 unaltered samples and 549 altered samples are provided as Microsoft Excel and as tab-delimited text.

Info
Geochemical database for igneous rocks of the ancestral Cascades Arc--southern segment, California and Nevada

Compilation of all available chemical data (more than 2,000 samples) for igneous rocks that constitute the southern segment of the ancestral Cascades magmatic arc.

Info
Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri, 2016-2017

Sample description, location, and geochemical analysis of Mesoproterozoic igneous rocks and iron oxide-apatite-rare earth element and iron oxide-copper-cobalt-gold deposits in this area. Data are provided in Microsoft Access and tab-delimited text formats.

Info
Geochronology and correlation of Tertiary volcanic and intrusive rocks in part of the southern Toquima Range, Nye County, Nevada

40Ar/39Ar dating, electron microprobe analyses and geologic mapping help clarify chronology and correlations of the numerous volcanic and intrusive units exposed in the area and interpret the petrogenesis of a few of the volcanic units.

Info
Geochronology and geology of late Oligocene through Miocene volcanism and mineralization in the western San Juan mountains, Colorado

New age determinations with descriptions of sample locations and analytical details.

Info
Gravity survey and interpretation of Fort Irwin and vicinity, Mojave Desert, California

Provides a view of alluvial basins, shapes, areal extents, and approximate thicknesses of alluvial fill. Gravity field is separated into density variations in the basement complex and distribution of Cenozoic fill with its 3-D thickness representation.

Info
In situ U-Pb dating of apatite and rutile from St. Francois Mountains IOA and IOCG deposits, southeast Missouri

Age dating of apatite and rutile samples from the iron oxide-apatite-rare earth element and iron oxide-copper-gold deposits hosted by the Mesoproterozoic rocks in this area. Data are provided in Microsoft Excel and CSV formats.

Info
Mineralogic causes of variations in magnetic susceptibility of late Pleistocene and Holocene sediment from Great Salt Lake, Utah

Results of magnetic susceptibility (MS) measurements and magnetic mineralogy of sediments sampled in three cores from the south basin of Great Salt Lake

Info
Operation Basement: Missouri Precambrian Sample Database

Sample locations, location descriptions, lithology, mineralogy, and geochronological relationships of drill holes that penetrated the buried Precambrian basement in this area. Detailed well log and cutting descriptions are included if available. Data are provided in Microsoft Access and tab-delimited text formats.

Info
SHRIMP U-Pb geochronologic data for zircon and titanite from Mesoproterozoic rocks of the St. Francois Mountains terrane, southeast Missouri, U.S.A.

Data for a geochronologic study of Mesoproterozoic rocks in this area. Zircon, plus one sample of titanite, from fifty samples of metaigneous rocks were dated by sensitive high resolution ion microprobe (SHRIMP). Data are provided in Microsoft Excel and CSV formats.

Info
Stillwater Complex Rock Outcrop Database

Polygons that describe areas of rock outcrop in the area of the Stillwater Complex, Montana from published reports and field mapping sheets. Includes both legacy data and outcrops from recent field mapping. This dataset contains overlapping polygons, as some areas had mapping from different sources that overlapped the same locations. Data are provided in shapefile format.

Info
Stratabound copper-silver deposits of the Mesoproterozoic Revett Formation, Montana and Idaho with a section on databases and spatial-data files for the geology and mineral deposits of the Revett Formation

Includes deposits, occurrences, and prospects; drill core logs and measured sections; and spatial databases for geologic maps, untested exploration areas, and permissive tracts for undiscovered mineral deposits.

Info
U-Pb zircon geochronology data from Eocene igneous rocks in the Stibnite-Yellow Pine mining district and vicinity, Idaho

Geochronology data to determine the ages of Challis igneous rocks in this area to help understand the stratigraphy and lithologic characteristics of these igneous rocks. Data are provided in CSV format..

Info